On the role of correlated double-electron capture in slow multiply charged N7+collisions with He

A theoretical study is made of single- and double-electron capture by totally stripped N 7+ ions from helium atoms in the collision velocity range nu =0.05-1 au. The calculation involves two-electron quasimolecular states and Nikitin's multichannel model. Adiabatic states were constructed by the configuration interaction method to derive the parameters of Nikitin's model around the crossings of the diabatic states. The calculation has revealed a new mechanism of single-electron capture. The capture has been shown to occur predominantly into states of the N 6+ ion (n=4) via correlated double-electron capture.